USB beverage warmer: crazy or brilliant?

I don’t know what to make of this USB-powered beverage warmer. On the one hand, it’s a weird use of a computer to power something distinctly non-computer related. And god knows I seem to get low-power warnings whenever I plug in anything but a mouse and keyboard into my computer via USB.

On the other hand, my coffee cup is currently sitting three inches from a USB port, with the remainder of my morning coffee, too cool to drink…